Recently, an attacker hacked into my database and stole all the passwords and usernames stored there. Needless to say, I had to change everything and it cost me time and money. What made the crime easy for the attacker is that I never encrypted any of the passwords in the database. I've learned my lesson and now I'm passing along that wisdom with this article about encryption in PHP. Using some of the encryption techniques that PHP offers, you can safeguard your information in various ways.

He lays the foundation for the series by talking about three different kinds of encryption that can help you protect your data - one-way encryption, symmetric (using a key) and asymmetric (shared key locking).